The role of paricalcitol on proteinuria

Paricalcitol is a synthetic vitamin D analogue acting on vitamin D receptor (VDR). The result is inhibition of PTH synthesis and secretion. Paricalcitol appears also to block the renin-angiotensin-aldosterone system. We evaluated the role of paricalcitol in the management of proteinuria of various aetiology. A total of 19 patients participated. Most had diabetic nephropathy; however patients with other types of glomerulopathy leading to proteinuria were also included. Paricalcitol 1-2 μg daily, according to response, was administered for three months. Serum Ca, PO4, Ca × PO4, PTH, creatinine clearance and albumin, as well as 24 hour urine protein were measured before and after treatment. Five out of 19 patients did not respond to the treatment. The remaining 14 patients had an average 32.9% reduction of proteinuria. The drug was well tolerated. Paricalcitol appears to have a role in the treatment of proteinuria. However, our study raises a question regarding why some patients do not respond to paricalcitol. Patients with proteinuria due to diabetic nephropathy seem to respond better than patients with glomerulopathy.